This is an interdepartmental and interinstitutional program to investigate fundamental and applied aspects of the pathophysiology and treatment of thrombosis and atherosclerosis. Components of the program include six independent but largely collaborative investigations into the physiology and biochemistry of blood platelets and their interaction with components of the vessel wall, with special emphasis on the relation of these phenomena to the pathogenesis of atherosclerosis and other responses to vascular injury and the biochemistry of the soluble clotting factors and the genetic factors involved in inheritance of their disorders.